What Causes Headache, Nausea And Vomiting?

had little chills ,headache,nausea,body weakness for about a week ,then i treated my self with mefloquin atesunate adult dose drug.took last does yesterday.but woke up with serious nausea and vomitting today and could not eat anything,then i took a tab of prometazine hcl,it's 4.17pm now..i just took some soup.but felling weal dizzy and nausea